Year	1=extremely inefficient to 7=extremely efficient
2007	3.6044776119403
2008	3.59645563007604
2009	3.6641199762
2010	3.8720315613
2011	4.1
2012	4
2013	4
2014	4
2015	3.97704834212905
2016	4
2017	4.1